在 MySQL 数据库上操作字符串答案

【问题标题】：Manipulate strings on MySQL database在 MySQL 数据库上操作字符串
【发布时间】：2020-03-14 17:46:09
【问题描述】：

我有这些字符串：X322-1-381128 和 X322-1-383128

我需要操作这些字符串以获得输出：

X322138128 和 X322138328

我试过这个解决方案没有成功，因为输出只有：X322138128

你能帮帮我吗？

mysql> SELECT
    'X322-1-381128' string,
    SUBSTRING_INDEX('X322-1-381128', '-', 1) a,
    SUBSTRING('X322-1-381128', 6, 1) b,
    SUBSTRING('X322-1-381128', 8, 2) c,
    SUBSTRING('X322-1-381128' ,- 3) d,
    CONCAT(
        SUBSTRING_INDEX('X322-1-381128', '-', 1),
        SUBSTRING('X322-1-381128', 6, 1),
        SUBSTRING('X322-1-381128', 8, 2),
        SUBSTRING('X322-1-381128' ,- 3)
    ) output,
    'X322-1-383128' string,
    SUBSTRING_INDEX('X322-1-381128', '-', 1) a,
    SUBSTRING('X322-1-381128', 6, 1) b,
    SUBSTRING('X322-1-381128', 8, 2) c,
    SUBSTRING('X322-1-381128' ,- 3) d,
    CONCAT(
        SUBSTRING_INDEX('X322-1-383128', '-', 1),
        SUBSTRING('X322-1-383128', 6, 1),
        SUBSTRING('X322-1-383128', 8, 2),
        SUBSTRING('X322-1-383128' ,- 3)
    ) output;
+---------------+------+---+----+-----+------------+---------------+------+---+----+-----+------------+
| string        | a    | b | c  | d   | output     | string        | a    | b | c  | d   | output     |
+---------------+------+---+----+-----+------------+---------------+------+---+----+-----+------------+
| X322-1-381128 | X322 | 1 | 38 | 128 | X322138128 | X322-1-383128 | X322 | 1 | 38 | 128 | X322138128 |
+---------------+------+---+----+-----+------------+---------------+------+---+----+-----+------------+
1 row in set

【问题讨论】：

标签： mysql string manipulate

【解决方案1】：

使用替换('X322-1-381128','-')

【讨论】：

选择替换('X322-1-381128','-','')
感谢回复，但输出必须包含10个字符，而输入是11个字符，仅替换是不够的

【解决方案2】：

看起来您的最后一个SUBSTRING 是错误的。您想删除所有- 和倒数第三个数字：

SELECT
  'X322-1-381128' string,
  SUBSTRING_INDEX('X322-1-381128', '-', 1) a,
  SUBSTRING('X322-1-381128', 6, 1) b,
  SUBSTRING('X322-1-381128', 8, 2) c,
  CONCAT(SUBSTRING('X322-1-381128' ,-4,1), SUBSTRING('X322-1-381128' ,-2)) d,
  CONCAT(
    SUBSTRING_INDEX('X322-1-381128', '-', 1),
    SUBSTRING('X322-1-381128', 6, 1),
    SUBSTRING('X322-1-381128', 8, 2),
    SUBSTRING('X322-1-381128' ,- 3)
  ) output,

  'X322-1-383128' string,
  SUBSTRING_INDEX('X322-1-383128', '-', 1) a,
  SUBSTRING('X322-1-383128', 6, 1) b,
  SUBSTRING('X322-1-383128', 8, 2) c,
  CONCAT(SUBSTRING('X322-1-383128' ,-4,1), SUBSTRING('X322-1-383128' ,-2)) d,
  CONCAT(
    SUBSTRING_INDEX('X322-1-383128', '-', 1),
    SUBSTRING('X322-1-383128', 6, 1),
    SUBSTRING('X322-1-383128', 8, 2),
    SUBSTRING('X322-1-383128' ,-4,1),
    SUBSTRING('X322-1-383128' ,-2)
  ) output;

由于您的字符串操作非常静态，您还可以使用以下更简单的解决方案：

SELECT 'X322-1-381128' string,
  CONCAT(LEFT(REPLACE('X322-1-381128', '-', ''), 8), RIGHT(REPLACE('X322-1-381128', '-', ''), 2))
UNION ALL
SELECT 'X322-1-383128' string,
  CONCAT(LEFT(REPLACE('X322-1-383128', '-', ''), 8), RIGHT(REPLACE('X322-1-383128', '-', ''), 2))

demo on dbfiddle.uk

【讨论】：